High frequency therapeutic apparatus

ABSTRACT

A high frequency therapeutic apparatus having a microwave oscillator connected to a power supply device, wherein the oscillator comprises a magnetron and an antenna assembly connected to the output portion of the magnetron; and the antenna assembly is formed of a helical antenna and a parabolic microwave reflector.

United States Patent Takahashi et al. 1- 1 Dec. 2, 1975 15 1 HIGH FREQUENCY THERAPEUTIC 3.304.400 2/1967 Ojelid 315/3953 x APPARATUS 3.377.562 4/1968 5121118.... INS/3,951 X 3.491810 2/1970 Valles 313/3951 [75] Inventors: Hirokazu Takahashi, Tokyo; Masao 3 540 050 11 970 Schmidt H 343 395 Kato, Komae, both of Japan 3,575.632 4/1971 K1110 et a1. 315/3951 3,623,118 l l/l97l Monser ct al 343/895 [731 Assgneei slllbaum Elem" 3,681,652 8/1972 Domenichini ct al. 315/3953 Kawasakh Japan 3,684.978 8/1972 Otaouro 328/253 [22] Filed: Mar. 4, 1974 Primary ExaminerSaxfield Chatmon, Jr. A 1. N 448,013 {2H pp 0 Attorney, Agent, or F1'rm-Obl0n, Fisher, Sprvak.

McClelland & Maier [301 Foreign Application Priority Data 571 ABSTRACT [52] U.S. Cl. 328/253; 315/3951; 315/3953; A high frequency therapeutic apparatus having a 328/230 crowave oscillator connected to a power supply de- [51] Int. Cl. ..H01J 21/18 Vice, wherein. the Oscillator Comprises a magnetron Fleld of Search 31, and an antenna assembly connected to the output per. 328/253; 343/895 tion of the magnetron; and the antenna assembly is formed of a helical antenna and a parabolic micro- [56] References Cited wave reflector UNITED STATES PATENTS 3,104,305 9/1963 Crapuchettes 315/3953 x 7 Clams 8 Drawmg F'gures v I J i 9 N S 9 I56 d 39 Q 32 -27 O US. Patent Dec. 2, 1975 Sheet 2 of3 3,924,196

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FIG. 5

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wfia & k jl m, i 4 a 139 o a: on n 66 1 oH o a L W f; 6 HQ 5 on M Q 4 H M w M M M M "no 0 O 0 o no US. Patent Dec. 2, 1975 Sheet 3 of 3 3,924,196

HIGH FREQUENCY THERAPEUTIC APPARATUS This invention relates to a high frequency apparatus and more particularly to a high frequency therapeutic apparatus using a magnetron.

Proper irradiation of microwave energy has come into use for recovery of muscular fatigue, therapeutic treatment of neuralgia and beauty treatment. The prior art high frequency therapeutic apparatus consists of a microwave oscillator and a microwave radiator or antenna device connected together by a high frequency cable used in transmission of relatively large power. Such conventional high frequency therapeutic apparatus is accompanied with the drawbacks that the connection of the high frequency cable is liable to be loosened, resulting in the unstable operation of said apparatus and also the occurrence of electric discharges. Further with a prior art high frequency therapeutic apparatus, difficulties are presented in transmitting the output power of the magnetron to the high frequency cable and then to the antenna device, thus reducing operating efficiency. Moreover, said apparatus is of complicated construction.

It is accordingly the object of this invention to provide a compact and efficient high frequency therapeutic apparatus comprising a microwave oscillator provided with a magnetron and an antenna assembly.

A high frequency therapeutic apparatus according to this invention is formed of a power supply device, microwave oscillator. The microwave oscillator comprises a magnetron and an antenna assembly connected to the end of the output portion of the magnetron. The antenna assembly conmprises an antenna and a parabolic, spherical or cone shaped microwave reflector.

This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 schematically illustrates a high frequency therapeutic apparatus according to this invention;

FIG. 2 shows the electric circuit of the high frequency therapeutic apparatus of FIG. 1;

FIG. 3 is a fractional lateral sectional view of the microwave oscillator of the therapeutic apparatus;

FIG. 4 is a sectional view on line 4-4 of FIG. 3;

FIG. 5 is a sectional view on line 55 of FIG. 3; and

FIGS. 6 to 8 present some modifications of the antenna assembly.

The high frequency therapeutic apparatus of FIG. 1 comprises a power supply device 11, microwave oscillator 12 and flexible cord 13 for electrically connecting said device 11 and oscillator 12. The microwave oscillator 12 radiates microwave beams having a frequency of, for example,2450 MHz in the direction indicated by the arrow 14.

FIG. 2 is an electric circuit diagram of the high frequency therapeutic apparatus. As seen from FIG. 2, the power supply device 11 comprises a low voltage transformer 111 for supplying power to heat the cathode of a magnetron; a high voltage transformer 112 for generating voltage being impressed between the anode and the cathode of a magnetron 15a; a power supplying cord 48 for operating cooling fans; and a high voltage rectifier 113.

The microwave oscillator 12 is formed, as shown in FIGS. 3 to 5, ofa magnetron device 15, antenna assembly 16 and cooling fan 17 and enclosed in a shield case 18. The magnetron device 15 comprises a magnetron structure 15a and a columnar permanent magnet 29 magneticallyconnected thereto. The magnetron structure 15a comprises an electron-emitting cathode member 21; a cylindrical anode member 22 concentrically disposed with the cathode member 21. with a resonant cavity provided around said cathode member 21; a pair of magnetic pole pieces 23, 241 fitted to both ends of the anode member 22; a cathode stem 25 projectively formed at the rear end of the anode member 22; and an output portion 26 also projectively provided at the forward end of said anode member 22. The magnetron structure 15a is hermetically sealed in vacuum. The permanent magnet 29 is magnetically connected to the magnetic pole pieces 23, 24 through magnetic yokes 27, 28. One magnetic yoke 28 is secured to a fitting base 30 made of nonmagnetic material. The fitting base 30 is opened at the center with a hole 30a penetrated by the antenna end portion 26 and antenna rod 31. The outer peripheral wall of the cylindrical anode member 22 of the magnetron 15 is fitted, as shown in FIG. 5, with a plurality of heat-radiating fins 32 radially arranged around the central axis of the anode member 22. Disposed opposite to the permanent magnet 29 are the elements of a filter circuit connected to the cathode member 21 of the magnetron structure 15a, namely, a lead 33, microwave attenuating ferrite bead 34, relay terminal 35 and capacitor 36 all received in an insulation member 37. A shield cap 40 is provided apart from the cathode stem 25 of the magnetron 15 so as to prevent unnecessary microwaves conducted through the cathode stem 25 from leaking to the outside. The shield cap 40 is opened with a large number of small ventilation holes 39 each having a diameter of, for example 5 mm so as to shut off microwaves. A cooling fan device including a vane 50 and a motor 51 is provided behind the shield cap 40.

The antenna assembly 16 is disposed on that end face of the magnetron 15 which faces the output portion 26. The antenna assembly 16 comprises a helical antenna 41 connected to the output portion 26 of the magnetron structure 1511 and a parabolic microwave reflector 42 so positioned as to reflect microwaves radiated backwardly from said antenna 41 in the form of beams to an irradiated object or in the direction of the indicated arrow 14. The reflector 42 may be shaped into a dome or conical form.

The cylindrical shield case 18 enclosing the magnetron structure lSa, antenna assembly 16 and cooling fan 17 are all wound with a tightening band 38 to be securely set in place. The fitting base 30 is screwed to the shield case 18, to which the end 42a of the microwave reflector 42 is fixed. The forward end of the shield case 18 is fitted with a cover 43 made of dielectric material permeable to microwaves such as glass or resin in such a manner as to enclose the helical antenna 41. The rear end of the shield case 18 is provided with a conductive cap 46 opened with a large number of ventilation holes 47. Further, that part of the shield case 18 which faces the outside of the microwave reflector 42 is perforated with a large number of ventilation holes 44 each having a cross section so designed as to prevent the passage of microwaves. The flexible cord 13 connected to the power supply device 11 includes a cooling fanconnecting cord 48, cathode lead 33 and grounding liine (not shown), all these components being drawn to the outside through the corresponding bushings 49.

With the high frequency therapeutic apparatus of this invention constructed as described above, the magnetron device 15 and antenna assembly 16 jointly constituting the high frequency section are incorporated in said apparatus in an integral body, elevating the output transmitting efficiency and enabling the entire apparatus to be made compact. Further, the microwave reflector 42 which reflects microwaves in the form of beams attains a high efficiency for therapeutic or beauty treatment. When the cooling fan device fitted to the microwave oscillator is so rotated as to cause cooling air to flow in the direction of the indicated arrow 45 of FIG. 3, then air is brought in through the numerous ventilation holes 44 formed in the peripheral wall of the shield case 18, passes between the heat radiation fins 32 of the magnetron l5 and also through the elements of the filter circuit for cooling, and is finally drawn out through the ventilation holes 39, 47 of the conductive shield caps 40, 46 disposed behind the oathode stem. Accordingly, a subject body on which microwaves are irradiated, for example, a human body is prevented from being exposed to cooling air and consequently feeling unpleasant. Even when the cooling fan is rotated to conduct cooling air in the opposite direction to that of the arrow 45, the cooling air strikes against the backside of the microwave reflector 42 and is discharged sideways through the ventilation holes 44 of the shield case 18, thus little affecting the subject body treated by microwave irradiation.

According to the modification of FIG. 6 of the antenna assembly 16 of this invention, holes 53, 54 are provided in the microwave reflector 42 and that part of the shield case 18 which is disposed ahead of said reflector 42, namely, the forward end portion of the case 18 so as to cool the helical antenna 41 and the output portion 26 of the magnetron structure a, thereby suppressing the increased temperature of the output antenna assembly 16 and enabling the therapeutic apparatus to be operated under a more stable condition. The above-mentioned ventilation holes 53, 54 have a cross section so designed as to prevent the passage of microwaves.

According to the modification of FIG. 7 of the output antenna assembly 16 of this invention, shunt bars 61 are stretched across the individual turns of the helical antenna 41 of the output antenna member 16 as well as across a series of turns so as to match the impedance of the magnetron structure 15a with that of the helical antenna 41, thereby elevating the efficiency of transmitting output from the magnetron structure 15a. Further, the joint action of the helical antenna 41 and microwave reflector 42 enables microwaves to be radiated in the form of beams having a far sharper directionality. When each turn of the helical antenna 41 is made to have an equal length to that of microwaves and shunt bars 61 are so fitted as to short-circuit those points on the respective turns of the helical antenna 41 which have the same phase, then said phases are forcefully made to coincide with each other, providing more stable microwave beams. The shunt bars have the further advantage of rendering the helical antenna 41 mechanically stronger against shock and vibration.

The modification of FIG. 8 of the antenna assembly 16 of this invention has a dielectric rod 65 concentrically inserted into the helical antenna 41. The forward I end of the dielectric rod 65 is fitted into an annular guide strip 67 projectively formed at the center of the inner wall of a dielectric cover 66 attached to the forward end of the shield case 18. The dielectric rod 65 is so inserted into the helical antenna 41 as to cause the end of the rearmost turn thereof to be brought to the center of the rear end face of said dielectric rod 65 and secured to the helical antenna 41 in several places. The rear end of the helical antenna 41 is connected, for example, by soldering to the antenna portion of the magnetron 15.

The dielectric rod 65 causes an electric field radiated from the helical antenna 41 to be concentrated in said rod 65 without escaping therefrom to the outside. Accordingly, the essentially occurring axial displacement of microwave beams delivered from a high frequency therapeutic apparatus is properly corrected and the microwave beams are made sufficiently narrow to be directed exactly, for example, to the affected part of a patient. Moreover, the narrow microwave beams reduce the number of turns of the helical antenna 41 and in consequence its axial length, thus minimizing the mechanical vibration of said helical antenna 41 during operation.

What we claim is:

l. A magnetron apparatus including a microwave oscillator comprising:

a magnetron device having an output portion and a cathode stem projecting in opposite directions;

an antenna assembly composed of a helical antenna directly connected to said output portion of the magnetron device'and a microwave reflector re fleeting in the form of a beam in a predetermined direction the microwave energy radiated from said antenna;

a shield case enclosing the magnetron device and the antenna assembly;

said microwave oscillator being connected electrically to a power supply with low frequency cord waves and fitted to the forward end of the shield' case.

2. A magnetron apparatus according to claim 1 wherein the antenna assembly has a dielectric rod concentrically inserted into the helical antenna, the rear end face of said dielectric rod being disposed close to the end face of the antenna portion of the magnetron device and the forward end of said dielectric rod being fixed to the central part of the dielectric rod cover.

3. A magnetron apparatus according to claim 1 wherein the microwave oscillator has a cooling fan received in that part of the shield case which faces the cathode stem of the magnetron device.

4. A magnetron apparatus according to claim 3 wherein the shield case has the part facing the microwave reflector opened with a large number of ventilation holes and the rear end covered by a shield cover which is also perforated with a large number of ventilation holes.

5. A magnetron apparatus according to claim 4 wherein the microwave reflector and that part of the shield case which is disposed ahead of the forward end of said microwave reflector are opened with a large number of ventilation holes.

6. A magnetron apparatus according to claim 5 wherein all the ventilation holes have such a cross section so designed as to prevent the passage of microtransformer for heating the cathode of the magnetron waves device and a power supplying cord for operating the 7. A magnetron apparatus according to claim 3 wherein said power supply includes a high voltage transformer, a high voltage rectifier, a low voltage 5 cooling fan. 

1. A magnetron apparatus including a microwave oscillator comprising: a magnetron device having an output portion and a cathode stem projecting in opposite directions; an antenna assembly composed of a helical antenna directly connected to said output portion of the magnetron device and a microwave reflector reflecting in the form of a beam in a predetermined direction the microwave energy radiated from said antenna; a shield case enclosing the magnetron device and the antenna assembly; said microwave oscillator being connected electrically to a power supply with low frequency cord means; the antenna assembly having a dielectric cover formed of dielectric material permeable to microwaves and fitted to the forward end of the shield case.
 2. A magnetron apparatus according to claim 1 wherein the antenna assembly has a dielectric rod concentrically inserted into the helical antenna, the rear end face of said dielectric rod being disposed close to the end face of the antenna portion of the magnetron device and the forward end of said dielectric rod being fixed to the central part of the dielectric rod cover.
 3. A magnetron apparatus according to claim 1 wherein the microwave oscillator has a cooling fan received in that part of the shield case which faces the cathode stem of the magnetron device.
 4. A magnetron apparatus according to claim 3 wherein the shield case has the part facing the microwave reflector opened with a large number of ventilation holes and the rear end covered by a shield cover which is also perforated with a large number of ventilation holes.
 5. A magnetron apparatus according to claim 4 wherein the microwave reflector and that part of the shield case which is disposed ahead of the forward end of said microwave reflector are opened with a large number of ventilation holes.
 6. A magnetron apparatus according to claim 5 wherein all the ventilation holes have such a cross section so designed as to prevent the passage of microwaves.
 7. A magnetron apparatus according to claim 3 wherein said power supply includes a high voltage transformer, a high voltage rectifier, a low voltage transformer for heating the cathode of the magnetron device and a power supplying cord for operating the cooling fan. 